This invention relates generally to machines used to fill bags with agricultural material, such as silage. The invention more particularly relates to the optimization of feed table speed via the addition of an electronically automated feed table control.
A bag filling machine and process as contemplated by the present invention involves placing silage material onto a feed table that runs toward a rotor connected to the inlet of a tunnel. The back of the tunnel is open and a bag secured to the tunnel receives the material conveyed by the feed table.
Ideally the silage deposits evenly on the feed table and is fed at a constant rate to optimize the filling of the bag. However, silage is a clinging material that does not readily flow. It is commonly delivered to the feed table in trucks and the material from the trucks is deposited as a sequence of large clumps. These large sequential clumps result in intermittent overloads and underloads with respect to feeding of the rotor. When the large clumps are fed into the rotor, the rotor often becomes clogged and overloaded. This in turn causes the speed of the rotor engine to decrease (circular). Presently, an operator manually slows, stops or even reverses the feed table to allow the overload to dissipate. However, by the time an operator is aware of the overload problem and then responds to that overload, a significant build up of silage at the rotor has occurred. Repeated overloading undesirably slows the overall filling of the bag. It is accordingly an object of the present invention to control silage feeding to the rotor automatically so as to minimize build up of silage at the rotor and thereby optimize filling of the bag.
In accordance with a preferred embodiment of the invention, a feed table measuring in the order of 8 feet in width and 15 feet in length receives truck loads of material, i.e., in the form of large and small mixed clumps of material. The feed table forces the clumps toward the rotor first engaging one or more beater bars (to at least partially break up the clumps) and then into the rotor that packs the silage into the machine""s tunnel where the material is compacted and then expelled into a storage bag. The feed rate is optimized at the highest feed table speed which does not lower rotor speed. It was determined that detection of overloading and quickly initiated controlled decreasing of the feed rate of the feed table prevents material build up at the rotor and provides for rapid recovery of rotor speed when slow down does occur.
An engine speed sensor is utilized to sense the reduction of rotor RPM. The engine speed sensor is connected to a control unit that in turn is connected to a proportional valve which meters hydraulic fluid to the hydraulic motor that drives the feed table. The proportional valve controls the volumetric flow rate of hydraulic oil flow to the feed table motor. By varying the orifice size of the proportional valve, the volumetric flow rate is increased or decreased (within established limits) and thereby dictates the feed rate of the feed table. Accordingly, the control unit receives a signal that indicates an overload. The control unit causes the proportional valve of the feed table motor to reduce orifice size decreasing the feed rate of the feed table. This occurs quickly and continuously as does increasing of orifice size upon increase of the engine""s speed (in RPM).
The invention will be more clearly understood and appreciated upon reference to the following detailed description and accompanying drawings.